A cam follower of this type is disclosed in DE 44 18 245 A1, viewed as generic. Tiny recesses or depressions introduced randomly into a run-on surface of the cam follower are proposed. Lubricant is stored in the recesses during the operation of the cam follower. The intention is to minimize friction in the valve drive.
However, in practice, these randomly introduced depressions do not result in any satisfactory minimization of friction, since sufficient lubricant is not accumulated in them. In addition, it is determined that the dynamic loadbearing proportion may also be too low, since, stated simply, the lubricant remains in the recesses.
Cam followers having run-on surfaces which, for example, have a channel-like grinding pattern, are known to the specialist world. During cam contact, some of the lubricant in front of the cam is forced away into the open in an undesired manner from the outwardly open channels. Here, too, it is clear that the formation of a loadbearing lubricant film is made more difficult.
In addition, it was hitherto the intention to create extremely “smoothly” finally machined run-on surfaces. Contrary to the assumptions, however, the wear is relatively high on such “smooth” surfaces, since the lubricant, so to speak, is “wiped away”.